An unpleasant element has crept into the predictably fierce debate on AWACS: the threat of an anti-Semitic reaction if the Senate rejects the sale. That notion, however couched, carries even greater significance than the sale itself and, if not silenced, could doom a transaction whose prospects are already at best marginal.

Certainly it is appropriate to warn the Israelis that a presidential defeat on this issue could exact a price in terms of U.S.-Israeli relations. Israel is a separate sovereign nation with interests not necessarily congruent with our own. The Israelis have, one assumes, carefully calculated the risks of their open opposition to this transaction.

On the other hand, for some time now we have heard suggestions, occasionally muttered by men of goodwill, that a defeat of the AWACS sale could cause a rebirth of anti-Semitism in the United States. This argument is of quite a different order. Whatever the motive of the people who raise it--usually frustration at the impact of the pro-Israel lobby--it cannot be seen as less than an ugly threat by some Americans against fellow Americans.

We are once again indebted to Richard Nixon for publicly noting the activity of "some American Jews" in the AWACS debate. Coming immediately after the leak of his 1971 tape, perhaps Nixon's comment can be explained as reflecting an academic ethnic interest. He just likes to count the number of Jews in a crowd.

Raising the specter of anti-Semitism is a direct attack on American democratic processes and values. Americans of various ethnic or national backgrounds have always paid particular attention to American foreign policy as it bears on nations with which they feel some identification. This is perfectly legitimate. President Reagan himself unabashedly appealed to American Jewish voters by emphasizing his conviction that Israel's strategic interests are closely aligned with our own.

Those who threaten anti-Semitism if the sale of AWACS is foreclosed should understand that there is a historical reason why this tactic is self-defeating and dangerous. During the 1930s and 1940s many American Jews, fearful of domestic anti-Semitism, did less than they should have to prevent the Holocaust. They carry a heavy burden of guilt because of their timidity. That pusillanimous attitude, we should hope, is gone forever.

Though it is a close question on the merits, I am persuaded that the impact of congressional disapproval of the AWACS sale would so badly cripple President Reagan's flexibility to maneuver in the Middle East that the sale should not be stopped. Notwithstanding my support of the sale, however, I would rather see AWACS defeated than see American Jews or non- Jews opposed to the sale modify their position for fear of anti-Semitism rather than on the merits.

The president would be well-advised to eschew any sympathy with this foolish tactic. As for those who make the threat, publicly or privately, they should realize they are not immune to response.